1. Field of the Invention
The present invention relates to a pusher of an IC chip handler, and more specifically, to a pusher for testing a plurality of IC chips one by one or simultaneously.
2. Description of the Related Art
A plurality of pushers are used for testing a plurality of IC chips simultaneously. In this case, the plurality of IC chips to be tested simultaneously are selected from, for example, a single production lot, and therefore, the external dimensions thereof such as the thickness must have been formed evenly. However in practice, these IC chips have production errors in, for example, the thickness thereof. Further, as a terminal pin of an IC chip and a test pin of a socket, various kinds of terminals such as a solder ball terminal, a film-shaped terminal, a spring-shaped terminal, and a pogo pin terminal are employed. The height of these pins also has errors from a set value owing to production errors or changes by aging. Furthermore, a leaf spring or a coil spring, etc. is employed as a test pin of a socket to be set to contact terminal pins at a predetermined pressure when they are arranged under pressure. However, the elasticity of these springs also varies, and changes by aging, which leads to incomplete contact.
In general, when an IC chip is set onto a socket, a pusher goes down a preset distance and stops. If the dimensions of each IC chip and terminal pin are normal, the terminal pin of the IC chip normally contacts the test pin at the test device side by the pusher at this position, and the test is performed. In this case, for example, if the thickness of the IC chip is larger than a set range, the IC chip is pushed more than required by the pusher when the pusher goes down a preset distance, so that the terminal pin of the IC chip and the test pin of the socket may be deformed or damaged. In the case where the IC chip is thinner than the set value, a pushing pressure of the IC chip to the socket by the pusher becomes insufficient if the lowering distance of the pusher is the preset value, so that test cannot be performed normally owing to incomplete contact of the terminal pin.
Further, there is a case where a plurality of IC chips are tested simultaneously by use of a plurality of pushers. In this case, the lowering distance of the pusher corresponding to each socket is set evenly. Therefore, if there is an error in the dimensions of the IC chip and the terminal pin, the IC chip is pushed more than the standard value, for example, when the IC chip is thicker than the set value, so that nonconformities such as breakage may occur. When the IC chip is thinner than the set value, test results may become incorrect owing to incomplete contact of the terminal due to insufficient pressure setting.
In order to solve these problems with the prior art, various countermeasures have been made. However, there are various types of IC chips to be tested, and testing costs will become high if pushers corresponding to these various specifications of the IC chips are to be prepared, which is not practical. Therefore, the realization of a pusher which can be applied in common to IC chips of various specifications would be desirable.